The invention relates to a wire-bonding system for bonding the contacts of semiconductor chips to leadframes, and in particular, to wire-bonding systems with multiple bond heads.
In the process of forming a semiconductor integrated circuit package, wire-bonders are commonly used to bond wires, for example, copper or gold wires on electrical contacts on semiconductor chips and corresponding leadframe leads in order to electrically connect the contacts on semiconductor chips to the leads on leadframes. Thereafter, the semiconductor chip is encapsulated with epoxy resin to form semiconductor packages and then each package is singulated. The wire-bonders include bond-heads comprising ultrasonic transducers, that use high-frequency vibrations to affix the wires to the contacts and leadframes.
Traditionally, wire-bonders have used single bond-heads due to the simplicity of implementation. Single bond heads avoid the problem of interference caused by multiple bond-heads, which would lead to inaccurate bonding if vibrations caused by one bond-head working on one work holder reverberates to an adjacent bond-head and work holder. Further, a single bond-head leads to a less complicated design in terms of machinery and work-flow.
Nevertheless, the use of single bond-heads have certain shortcomings. One disadvantage is that single-head wire-bonders lead to greater footprints if several wire-bonder machines are to be implemented. Thus, if multiple wire-bonders are implemented in an in-line system, valuable floor-space is wasted as a result of the larger foot-print. Further, having single bond-heads slows down the wire-bonding process if, for instance, different bonding processes like alternate patterns or different wire sizes are to be performed on the same leadframe. If the wire-bonder has multiple bond-heads on the same system that are substantially adjacent to each other, the different bonding processes can be carried out consecutively with less transportation time required to transfer the leadframe from one bond-head to another.
Thus, the invention seeks to provide an improved wire-bonding system comprising multiple bond-heads to avoid some of the disadvantages of the prior art consisting of single bond-head systems.
Accordingly, the invention provides a wire-bonding apparatus for forming electrical connections between a semiconductor chip and a leadframe, comprising a plurality of bond-heads associated with a plurality of work holders on said wire bonding apparatus for holding a plurality of leadframes, wherein each bond-head of the apparatus is capable of independent bonding operation simultaneously with the other bond-heads, without synchronization of movement with the other bond-heads.
It will be convenient to hereinafter describe the invention in greater detail by reference to the accompanying drawings which illustrate one embodiment of the invention. The particularity of the drawings and the related description is not to be understood as superseding the generality of the broad identification of the invention as defined by the claims.